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Identifying dispersal mechanisms of Ceratocystis fimbriata, causal agent of black rot, within sweetpotato storage and packing systems
Madison Stahr - NCSU. Lina Quesada-Ocampo- North Carolina State University

Ceratocystis fimbriata is one of the most devastating pathogens of sweetpotato, yet little is known about the pathosystem. To better understand pathogen dispersal in the sweetpotato production system, this study aimed to: i) assess the role of dump-tank water in dispersal and to ii) identify potential insect vectors. In water tests, C. fimbriata spore suspensions were diluted (0,5,50,500, & 5000 spores/mL), aged (0,24,48,96, & 144 hrs), or heated/chilled (10,23,35, & 45?C) to test for the effects of inoculum density, age, and water temperature on dispersal, respectively. Wounded and non-wounded sweetpotatoes were soaked in water treatments for 20 min, stored at 29?C for a 14-day period, and rated for incidence every other day. To identify insect vectors, sticky traps were placed in sweetpotato storage facilities for one-week and insects were visually identified. Water tests showed temperature had no impact on disease incidence, but incidence did significantly decrease as inoculum concentration decreased and inoculum age increased. The insect survey found that overall, significantly more Drosophila species were recovered than any other insect. D. hydei, a relatively easy to maintain species which comprised 85% of the samples, was selected as a good candidate for future vector studies. These findings advance our knowledge about the black rot pathosystem, as well as inform integrated management approaches for sweetpotato black rot.